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This past week I noticed a few spider mites in my all hydroton/mineral salts hydro system. Caught 'em early, sprayed with the usual 3-5% oil 0.5% surfactant mix, next day twice with plain water, 2 days later, brewed worm tea spray, next day a weaker oil mix. No more spider mites. But some of the plants were looking really weak. In addition to the little brown burn marks that even that little bit of oil will cause on peppers (peppers seem to be particularly sensitive to oil, unlike a lot of other plants), a couple seemed to be wilting a bit. I should have known then... but, I attributed this to the stress of being moved around, bumped around, lifted out of the little DWC bins, taken to the bathroom and being sprayed with oil etc... Dumb. Real dumb. 

I was away from my house (got snowed in elsewhere) for a day and a half, and when I got in today, 2 plants were half dead and a third one (of four total) is looking iffy. I know now, Pythium (or the "thing who's name shall not be spoken aloud") is the culprit.

These plants are just about done with their veg stage and are starting to enter flowering. I've only seen this before in seedlings. Most all of what I've heard/read from the hydro world is that there is 'nothing you can do about it'. Cut your losses, sterilize, start over and try to keep your water temps below 25C.

A couple of months ago I read a post here by Ricky Flickenger about his mold problem, and how he raised his pH slightly and took care of his long standing battles with the mold. At that very same time I had a small Basil plant with a nasty lesion on the stem right above and below the hydroton . There was a greyish-white fuzz on the hydroton as well (I thought, some kind of Botrytis at the time, but IDK). Reading Ricky's post gave me an idea... I took that plant and dunked it (net pot and all) in a solution of water pH 8.8 a number of times throughout the day, rinsed it and put it back. (Did a water change too...These are all fish-less systems). That Basil is still growing nicely today almost two months later.  

Back to the peppers. I did a water change re-upped the nutes back to 1.5 EC, but left the pH at 7.6, and have been spraying the roots and base of the stems with water pH 9. Half of me thinks this is just wishful thinking and that these actions are futile...Has anyone ever tried something like this? Combating Pythium with pH? I mean on a very small/very non-commercial scale of course. Am I just doing more damage the plants this way?

The reason I chose pH 9 is because TC has taught us that you can bottle and age urine for a period of time until the pH goes up to 9, and the urea content has then been turned into ammonia. And that this has the effect of killing off many pathogens. I understand that these things may not be connected, but that is why I chose 9 and not 8 or 10 if anyone was wondering...

Any help/ideas/experiences with Pythium and pH would be greatly appreciated (even if it's discouraging). I know that a lot of AP folks are way more adventurous than the hydro crowd, so I though I'd ask...

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im a huge fan of Actinovate and Actinoiron

the actinovate covers a wide range of issues and offers other bacterial benefits.


Im in the "never heard of pythium in ap" group

we recently heard about "Root Mites"... they say that many rot and root issues are misdiagnosed root mite damage


i sure have seen every other rot, bug, and mite problem there is..  in just about every ap system.

have you had any issue in the larger system?


How safe is Actinovate for the fish... and at what dose/100gal of AP system water? Does one need to apply several doses in succession?

From my understanding it won't take out your bio-filter as it can work with the bacteria, however, more importantly is what it does to the fish, both short term and long term... especially for those of us that eat the fish.

Does Actinovate destroy Pythium + oospores within the system or does it simply supress it, so that should an ideal situation arise, it would flare up again?

Plants already infected... do they recover 99-100%?

We're stuck with trying to deal with Pythium (must have come from the one and only time we bought dwarf fruit trees from a supplier and put them into the system, we always otherwise grow from seed). In Jan we completely sterilized the system as best we could and began life over again in Feb. Spores must have been on surfaces we could not easily get to, really hard to say. We used pool chlorine in essence to wipe out the entire system, maintaining a level above 5ppm, as it does break down with the presence of organic matter.

We just sent in plants for analysis since it was clear something was up... and yes, the problem is still there.

Many thanks,


Hey Randall, I'll swap you a fall half runner bean that is outstanding for some Chili Teppin seeds.

Randall Wimbish said:

I like my peppers as well. We have a native pepper that grows well because it is drought tollerant. It is called Chili Teppin, Chili Pequine and Texas Bird Pepper.  It is tiny, about the size of a tic tac, but comes with a lot of flavor and packs a punch with capsium. Very tollerant to any kind of fungus and insect. I have a few plants that get up to 6 feet tall during the growing season. They are perrinials and mine have survived temperatures of 18 degrees F.  I just cut them back every spring and they grow back.   I have tried them in h.p. and a.p. and they don't like all the water.   I can take a bag of all the different kinds of peppers i grow to work and share with my fellow workers that are mostly from a country south of our border and they will eat the Chili Pequines first and want more.

@Rob, hehe I'm a "huge fan too" but only at a distance, as there is no distributor for Actinovate here, nor is there any similar product (streptomyces lydicus) sold here.

Thankfully, no. I've not had any issues in the larger system.

@Shaun, I'm real sorry that you have had to go through all that. Actinovate, (according to the manufacturer) should be used as an inoculant, so I'm not sure how successfully it would actually kill oospores? It seems like the thing to do would be to sterilize, then inoculate as you cycle your system back up. The more beneficial microbes you have colonizing niche surface environments, the better. It will give the pathogen less 'real-estate' to work with, suppressing it's proliferation.

But for actually killing the pathogen and hopefully it's spores, you need something of a different nature. Non-biological. My "chemical" of choice for laying waste to anything microbial, fungal, oomycetic... is Oxygen.

Sodium perborate and/or sodium percarbonate are both solid crystalline/powder forms of hydrogen peroxide (H2O2). It can be stored much, much longer (and it takes up much less space) than liquid H2O2... and you can mix up the desired strength yourself according to your needs. It is an awesome and powerful sterilizing and cleaning tool. The oxygen released when it comes into contact with water will 'fry' any living microbes present in the column. It quickly degrades into mostly O2, and water molecules...and an insignificant amount of carbonate.

After sterilizing a system with anything, the second step is to inoculate it with beneficials. This step is often over looked, which is bad. A fresh sterile system is a heaven sent playground for aggressive and persistent pathogens to colonize.

Actinovate (streptomyces lydicus strain WYEC 108) doesn't appear to have any effect on freshwater invertebrates or fish. It appears to be non-toxic, non-allergenic and non-pathogenic to our aquatic friends (or any other non-target species).

I'm no 'authority' or 'expert' or anything, but if I were having problems and if that product were available here, I'd have no qualms about using it in a system from which I harvested and ate fish from.

 Hello Vlad... thank you for your input and thoughts.

You have certainly pointed out I think the one mistake that has left us back where we were... I just didn't think about it at the time since when we first fired up the system we simply let nature take it's path, we did not inoculate with anything. I have a feeling had we inoculated the system first with with something like Actinovate then MycoGrow we would not be where we are. What you say makes perfect sense. The question I guess is does one establish the biofilter first within the system (I have both a separate moving bed bio filter and media beds) and then inoculate?

This next time round we'll try this... after sterilizing, inoculate the system first with a product like Actinovate, then give the bio-filter a chance to get established with a little help from "bacteria in a bottle" and then add a good dose of MycoGrow. Then begin seeding. Thoughts?

I will definitely look into the crystaline forms of hydrogen peroxide, that's a great way to do the final clean up once we've removed as much of the organic materials as possible.

Cheers, Shaun.

Another source of the infection might be your seed starting media, if you use loose peat to mix up your germination mix, you may be bringing in pythium.

Hey TCLynx... no peat used, all germination is done in Rapid Rooters only. Would not be good if this came from them...

Good Luck.

I would say inoculate both the bio-filter bacteria and the Actinovate about the same time after you get it all cleaned up again.  But that is purely a guess on my part.

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